Revisiting the limits of photon momentum based optical power measurement method, employing the case of multi-reflected laser beam
Revisiting the limits of photon momentum based optical power measurement method, employing the case of multi-reflected laser beam
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DOI：
10.1088/1681-7575/abc86e
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发表时间：
2021-02-01
期刊：
影响因子：
2.4
通讯作者：
Froehlich, Thomas
中科院分区：
文献类型：
--
作者：
Vasilyan, Suren;Lopez, Marco;Froehlich, Thomas
在这项工作中，我们回顾了基于光子动量的光功率测量方法的可行性和精确度，该方法利用被困在光学腔中的多反射光束引起的放大效应。测量从高反射表面吸收和重新发射的光子的总动量传递(激光从光学镜面的反射)作为力，提供了测量光学功率的可能性，并可直接追溯到SI单位。试验测量是在两个不同的计量实验室进行的：伊尔梅瑙技术大学的质量/力实验室和PTB的洁净室激光辐射实验室，其便携式测力装置由两个电磁力补偿天平组成。我们通过基于光子动量的方法，将使用测力装置进行的光功率测量的结果与使用校准的参考标准探测器进行的结果进行了比较，该探测器可追溯到PTB的光学功率的主要标准-低温辐射计。在波长为532 nm的1W至10W的光功率范围内进行了比较，这相当于上限处约2000nN的力，在33次反射的情况下产生约2.3%的相对标准不确定度。因此，将µN到NN级别的高精度测力技术与实现激光束镜面多反射配置所需的光学设置相结合，其中具有超高反射镜(>；99.995%)的宏观光学腔可调节地悬挂在力传感器上，取决于所需的反射几何形状，我们表明，随着名义上施加的光功率、激光光束反射次数或反射镜的反射系数的进一步增加，光功率测量的不确定性可以显著降低。
In this work, we review the viability and precision of the photon-momentum-based optical power measurement method that employs an amplification effect caused by a multi-reflected laser beam trapped in an optical cavity. Measuring the total momentum transfer of the absorbed and re-emitted photons from a highly reflective surface (reflection of the laser beam from an optical mirror) as a force provides the possibility of measuring the optical power with direct traceability to SI units. Trial measurements were performed at two different metrology laboratories: the laboratory for mass/force at the Technical University of Ilmenau, and the clean room laser radiometry laboratory at PTB, with a portable force measurement setup consisting of two electromagnetic force compensation balances. We compared the results of the optical power measurements performed with the force measurement setup, via the photon-momentum-based method, with those performed using a calibrated reference standard detector traceable to PTB's primary standard for optical power, the cryogenic radiometer. The comparison was carried out for an optical power range between 1 W and 10 W at a wavelength of 532 nm, which corresponds to a force of approximately 2000 nN at the upper limit, yielding approximately 2.3% relative standard uncertainty in the case of 33 reflections. Thus, conflating the high-precision force metrology technique at mu N to nN levels with the optical setup required to achieve specular multi-reflection configuration of the laser beam, where a macroscopic optical cavity with ultra-high reflective mirrors (>99.995%) can adjustably be suspended from the force sensors, depending on required geometry of reflections, we show that the uncertainty of the optical power measurements upon further increase of the nominally applied optical power, the number of laser beam reflections, or the reflectivity coefficient of the mirrors can be markedly reduced.